Many optical processing systems use an SLM (spatial light modulator) to modulate a beam of light, which modulated beam is then processed by various optical elements. The processed light is often detected using a CCD array detector or another type of PDA (planar array detector). Such optical systems utilize discrete optical elements, such as the SLM and detector, even when the nature of processing is continuous, for example using a Fourier lens. This results in a mismatch between the input and output, in some systems. In some cases, also some of the optical processing elements are discrete.